Fix failing resource back compat checks

[lmolkova]

Back-compat checks are failing since 1.28.0 was released with

Violation: Resource 'service' cannot remove required/recommended attributes (missing '{"service.name", "service.version"}')
  - Category         : backward_compatibility
  - Type             : semconv_attribute
  - SemConv group    : service
  - SemConv attribute: 
  - Provenance: /home/weaver/source

Violation: Resource 'telemetry.sdk' cannot remove required/recommended attributes (missing '{"telemetry.sdk.language", "telemetry.sdk.name", "telemetry.sdk.version"}')
  - Category         : backward_compatibility
  - Type             : semconv_attribute
  - SemConv group    : telemetry.sdk
  - SemConv attribute: 
  - Provenance: /home/weaver/source

E.g. here #1454

It happens because we marked service and telemetry.sdk groups as stable, but there are two groups with the same name and they are being compared against each other.

This is being fixed in #1423, in the meantime we need to compare stable groups.